The beard that develops during one's stint with sickness, resulting in a lack of desire, need, or ability to trim or shave facial hair. The result is typically a large, unruly, homeless lumberjack looking beard.

The outcome of being very drunk, passing out with your head tilted right back and spewing up. The sick then, assuming you don't choke and die, will run over the lips down the chin and over the cheeks. The sick is left to dry until you re-gain conciousness. When you awake, you will find you are left with a fully set sick beard. Sick beards are very fashionable among the homeless.

Chad: Hey Bro.. Did you see that guy in the doorway back there?
Tim: Hells yeah man! He was sportin a serious sick beard!

Alex: (looking in mirror) WOAH. Look at the size of that sick beard. I must have had a great night.